The aim of this study is to determine different culture media and temperature values on the growth rate of Desmodesmus protuberans (F.E. Fritsch & M.F.Rich) E. Hegewald, and to investigate antimicrobial and antioxidant potency of the crude extracts. The microalga isolates from Egirdir Lake in Isparta (Turkey) was identified as D. protuberans and included in Ege University Microalgae Culture Collection. D. protuberans was cultivated at two temperature regimes (22 and 28 degrees C) and growth media (BBM, BG-11 and RD medium) under the light intensity of 75 mu mol m(-2) S-1 for testing the impact of different environmental conditions on the growth rate. All of the productions of D. protuberans biomass were extracted with methanol and investigated the antimicrobial and antioxidant activity. Antimicrobial activities of the extracts of alga were tested by disc diffusion assay against five Gram-positive and four Gram-negative bacterial strains and against the yeast Candida albicans. The methanol extract of the biomass from BBM medium (28 degrees C) showed the highest growth inhibition effect on C. albicans, while RD medium (22 degrees C) extract showed the highest antioxidant activity. These results demonstrated that the differences in the bioactivity of biomasses are stemmed from different temperature and media conditions.